This invention relates to welding sheet materials. Thermoplastic materials made be joined using a variety of welding techniques. In an exemplary welding process, dies are used to form welded seams in one or more thermoplastic films. The dies include surface details (e.g., raised edges) that correspond to the locations where the welded seams are to be formed. Sheets of thermoplastic material are positioned between the dies and energy applied to the dies to melt the thermoplastic and form welded seams.
A drawback to this type of welding is that specific dies must be used for specific products.